1. Field of the Invention
The present invention relates to a thin-film magnetic head, a head gimbal assembly, and a hard disk drive.
2. Related Background Art
As hard disk drives have been achieving higher recording densities, further improvements in thin-film magnetic heads have been in demand. Composite thin-film magnetic heads having a structure in which a magnetism detecting element such as magnetoresistive (MR) element and a magnetic recording element such as electromagnetic coil element are laminated have been in wide use as a thin-film magnetic head, while these elements read/write data signals from/onto magnetic recording media.
The electromagnetic coil element comprises a coil which generates a magnetic field in response to a current applied thereto and a magnetic pole which forms a path for the magnetic field and releases the magnetic field from a desirable place in a medium-opposing surface. The coil is typically covered with an insulating resin layer (see, for example, Japanese Patent Application Laid-Open Nos. 10-64013 and 11-31307).
When a current flows through a coil at the time of a writing action, the coil is heated by the Joule heat. When the temperature rises in the coil and its surroundings because of the heating of the coil, adverse effects such as generation of thermal stresses and deterioration in performances of the magnetism detecting element occur as described in Japanese Patent Application Laid-Open No. 2001-110015. Therefore, it is necessary to fully dissipate the heat generated from the coil.